Pathogenesis 745 



stated openly that he had cultivated the leprosy bacillus, but now 

 admitted frankly that he was mistaken." 



The interesting question that awaits settlement now seems to be, if 

 these bacilli, and specially the bacillus of Duval, are not Bacillus 

 leprae, what are they? What relation do they bear to leprosy? 



Pathogenesis. — Melcher and Ortmann* introduced fragments 

 of lepra nodules into the anterior chambers of the eyes of rabbits, 

 and observed the death of the animals after some months, with what 

 they considered to be typical leprous lesions of all the viscera, 

 , especially the cecum; but the later careful experiments of Tashirof 

 show that most of the lower animals are entirely insusceptible to 

 infection with the lepra bacillus, and that when they are inoculated 

 the bacilli persistently diminish in numbers and finally disappear. 



Nicollet found it possible to infect monkeys with material rich 

 in lepra bacilli taken from human beings. The lesions appeared 

 only after an incubation period that was in some cases prolonged 

 from twenty-two to ninety-four days. The lesions persisted but a 

 short time and the monkeys recovered in from thirty to one hundred 

 and fifty days. 



Clegg§ and Sugai|l found Japanese dancing mice susceptible 

 to infection with leprous material, the micro-organisms not remain- 

 ing localized at the seat of inoculation, but disseminating through- 

 out the animal's body. Their observation has been confirmed by 

 Duval,** who laterft was also able to infect' monkeys — Macacus 

 rhesus — with pxu-e cultures of the organism and produce the typical 

 disease. 



Very few instances are recorded in which actual inoculation has 

 produced leprosy in man. ArningJt was able to experiment upon a 

 condemned criminal, of a family entirely free from the disease, in 

 the Sandwich Islands. Fragments, of tissue freshly excised from a 

 lepra nodule were introduced beneath his skin and the man was 

 kept under observation. In the course of some months typical 

 lesions began to develop at the points of inoculation and spread 

 gradually, ending in general leprosy in about five years. 



Sticker §§ is of the opinion that the primary infection in lepra 

 takes place through the nose, supporting his opinion by observa- 

 tions upon 153 accurately studied cases, in which — 



I. The nasal lesion is the only one constant in both the nodular 

 and anesthetic forms of the disease. 



* "Berliner klin. Wochenschrift," 1885-1886. 



fCentralbl. f. Bakt. u. Parasitenk" (Originale), March 12, 1902, xxxi, No. 

 7. p. 276. 



t "Semaine medicale," 1905, No. 10, p. no. 



§ "Philippine Journal of Science," 1909, iv, 403. 



II "Lepra," 1909, vni, 203. 



** "Journal of Experimental 'Medicine," 1910, xn, 649. 

 ttlbid., i9ii,xni, 374. 

 U "Centralbl. f. Bakt.," etc., 1889, vi, p. 201. 



§§ "Mittheilungen und 'Verhandlungen der internationalen wissenschaftlichen 

 Lepra-Konferenz zu Berlin," Oct., 1897, 2, Theil. 



